Hot repairing materials which are used to fill cavities or depressions caused by damage to lining refractories by utilizing flowability of the materials have been widely used, particularly for BOF (Basic Oxygen Furnace), electric furnaces, AOD furnaces, ladles, etc.
As such hot repairing materials are materials that are generally charged into a furnace at high temperatures and are able to fill cavities caused by damage because of the natural flow of the materials themselves to exhibit effects as repair materials, there are required to have good flowability and high adhesive strength with lining surfaces.
As such materials, it is general to have a type such as a plastic, massive, or solid state in which coal-tar pitch is added to a basic aggregate and heat-kneaded or sometimes creosote etc. are added to knead at normal temperature, or a powder state etc. in which powder or granular pitch is added to the aggregate. Coal-tar pitch has been widely used as a binder for a hot repairing material or a baking material, as it has properties wherein the residual carbon after heating is high, forming good carbon bonds and it has a relatively low price.
However, as the volatile gas of pitch contains harmful substances, strong fuming is generated during hot repairs to deteriorate the working environment.
Pitch looses volatile matter and carbonizes by decomposition and polymerization reactions at about 500.degree. C. or more. However, as it is a mixture of organic matter of various components, the reaction proceeds in a complicated fashion. For this reason, it takes a long time for the pitch to carbonize at 500.degree.-600.degree. C. i.e. for the hot repair material or baking material to harden.
Various attempts have been proposed to improve the defects of hot repair material or baking material which use such coal-tar pitch type binders.
For instance, in Japanese Patent Publication No. 59-17072, a material is disclosed in which a novolak type resin is added to a basic aggregate and heat-kneaded to obtain a massive solid body. However, the material begins to set and carbonize on its surfaces before the inside of the massive body begins to melt and soften. Therefore, in many cases, it does not flow as a whole and even if it partially flows, it is difficult to obtain a satisfactory repair effect because warpage is great and adhesive properties are unstable on the periphery portions extended by flowing.
Also, in Japanese Patent Application Laid Open No. 61-242962, a repair material has been disclosed, in which granular type coal-tar pitch, granular or liquesfied low molecular weight thermoplastic resins and an organic solvent are added to basic aggregate and kneaded to obtain a block state material. However, this repair material requires mechanical pressure for adhesion and is poor in natural flowability, so it is difficult to fill in concave portions as a fluid.
Further, in Japanese Patent Publication No. 62-28112, formulations have been disclosed, in which phenol resin or melamine resin and powdery carbon are added to a thermoplastic material selected from a group comprising aromatic petroleum resins, petroleum pitch and heavy oil instead of coal-tar. However, it is not sufficient for the repair of converter charging side walls etc. which requires abrasion resistant properties, as the petroleum thermoplastic material has poor strength after carbonization and hardening.
In Japanese Patent Application Laid Open No. 63-74973, a repair material has been disclosed in which paraffin is added to a material comprising a basic refractory aggregate, a bituminous material such as coal-tar etc. and a thermosetting resin such asphenol resins etc. and which is then kneaded to form it into small lumps. It has advantages in that the use of paraffin allows low temperature kneading and fuming during kneading is prevented. However, it has defects in that surface hardening of the lumps is fast when they are thrown into a high temperature furnace and it is difficult for each of the lumps to unit with each other through melt-softening.
Also, in Japanese Patent Application Laid Open No. 63-156081 a material in which refractory materials and powdery resin are kneaded with polyhydric alcohol has been disclosed. However, it does not flow at all and has scarcely any adhesive strength, particularly when a thermosetting type resin was used as the powdery resin.
In this way, since coal-tar pitch, takes a long time to harden and remains in a softened for quite sometime after heating, it shows some flowability, but it causes the generation of harmful substances and repairs require long hours. On the other hand, in the case of a resin type bonding agent, hardening begins on the surface of the agent before softening of the inside of the hot repair materials or baking materials by heating begins. For these reasons, it can not flow as a whole and it has problems in adhering to lining surfaces and tends to be difficult to form into monolithic bodies.
The present invention has been invented to solve the problems described above. The object of the present invention is to provide a monolithic refractory having excellent flowability under heat, that controls warpage phenomena which readily generates on the periphery of a lined body, and high adhesion by using a phenol resin as a bonding agent capable of forming good carbon bonds.